Database Design

Check out the following posts, they will give you some ideas.

https://tray2.se/posts/database-design

https://tray2.se/posts/database-design-part-2

https://tray2.se/posts/properly-formed-foreign-keys-are-your-best-friends

https://tray2.se/posts/use-a-view-instead-of-a-complex-eloquent-query-in-your-laravel-application

https://tray2.se/posts/using-table-triggers-to-log-changes-in-your-database-tables

I think an important reason could be that the idea is, that a Laravel application theoretically is supposed to be db independent.